RIPE

Plants convert sunlight into energy through photosynthesis; however, most crops on the planet are plagued by a photosynthetic glitch, and to deal with it, evolved an energy-expensive process called photorespiration that drastically suppresses their yield potential. Today, researchers from the University of Illinois and U.S. Department of Agriculture Agricultural Research Service report in the journal Science that crops engineered with a photorespiratory shortcut are 40 percent more productive in real-world agronomic conditions.

This week, families across the U.S. will gather around Thanksgiving tables in a traditional celebration of the season’s bounty. By improving how key crops transform sunlight into yield, Realizing Increased Photosynthetic Efficiency (RIPE) will one day help farmers put food on more tables worldwide, especially where it is needed most.

Plants such as soybeans and wheat waste between 20 and 50 percent of their energy recycling toxic chemicals created when the enzyme Rubisco—the most prevalent enzyme in the world—grabs oxygen molecules instead of carbon dioxide molecules. Increasing production of a common, naturally occurring protein in plant leaves could boost the yields of major food crops by almost 50 percent, according to a new study led by scientists at the University of Essex published today in Plant Biotechnology Journal.

Cassava is a staple in the diet of more than one billion people across 105 countries, yet this “orphaned crop” has received little attention compared to popular crops like corn and soybeans. While advances in breeding have helped cassava withstand pests and diseases, cassava yields no more today than it did in 1963. Corn yields, by comparison, have more than doubled.

Agriculture already monopolizes 90 percent of global freshwater—yet production still needs to dramatically increase to feed and fuel this century’s growing population. For the first time, scientists have improved how a crop uses water by 25 percent without compromising yield by altering the expression of one gene that is found in all plants, as reported in Nature Communications.

The top leaves of crops absorb far more light than they can use, starving lower leaves of light. Scientists designed plants with light green leaves with hopes of allowing more light to penetrate the crop canopy and increase overall light use efficiency and yield. This strategy was tested in a recent modeling study that found leaves with reduced chlorophyll content do not actually improve canopy-level photosynthesis, but instead, conserve a significant amount of nitrogen that the plant might be able to reinvest to improve light use efficiency and increase yield.

Plants evolved over millions of years into an environment that has dramatically changed in the last 150 years since the Industrial Revolution began: carbon dioxide levels have increased 50 percent, and the average global temperature has increased by nearly 2 degrees Fahrenheit. While natural adaptation has been unable to keep up, scientists have developed tools to simulate millions of years of evolution in days to help plants adapt.

Instead of turning carbon into food, many plants accidentally make a plant-toxic compound during photosynthesis that is recycled through a process called photorespiration. University of Illinois and USDA/ARS researchers report in Plant Cell the discovery of a key protein in this process, which they hope to manipulate to increase plant productivity.

Researchers report in the journal Science that they can increase plant productivity by boosting levels of three proteins involved in photosynthesis. In field trials, the scientists saw increases of 14 percent to 20 percent in the growth of their modified tobacco plants. The work confirms that photosynthesis can be made more efficient to increase plant yield, a hypothesis some in the scientific community once doubted was possible.